The present invention generally pertains to a surgical wire inserter adapted to insert a circular prosthetic device into or through bones to provide support and fixation while the bone structure is mending or to provide anchorage for traction but more particularly pertains to a rotary wire inserting device utilizing a sterile wire pack provided with flats to provide an anti rotational key.
In the prior art a prosthetic wire device usually 3 to 9 inches long and circular in cross section is generally inserted into the bone by means of a pre-drilled hole or more commonly by driving the wire with a suitable drill chuck and letting the wire bore its own hole by means of a spade or trocar tip. A trocar point is the point most commonly used on such wires. One such device which has been used to insert wires is a device called a Loth-Kirschner extension drill. The drill is hand operated with the drill bit being rotated by a suitable gearing which is turned by a handle much like that of a fishing reel.
Another device which has been used is a pneumatic wire driver manufactured by the Stryker Corporation. This device is a hand held device with a trigger. An air supply is connected to the device by way of hoses which pass through the handle of the gun causing the wire to rotate so that it obtains a sufficient torque to be driven into the bone.
Generally speaking the prosthetic wires which are used in both of these instruments and wires which are used in the operating room are circular in cross-section ranging from 0.028 to 0.062 inches in diameter and are primarily provided with a ground spade point or a trocar point. The spade point has a cutting action by virtue of the cutting edges and consequently drills into the bone with relative ease. However, because the spade point drills a hole equal in diameter to the wire, the wire is relatively loose when it is inserted. The trocar point has more of a spreading action rather than a cutting action and therefore drills with relative difficulty which results in a tightly held wire when installed since it does not drill a clearance hole for the wire.
Because of the circular cross section and small diameter of these wires they are difficult to hold in a chuck tightly enough to prevent slipping during installation.
The present invention incorporates a wire having a tip which provides the cutting ease of the spade tip while maintaining the holding properties of the trocar tip. Furthermore, the invention provides anti rotational features on the wire which eliminate the rotational slippage of the wire in the drill chuck during installation. The novel instrument which is used to rotate the wire contains a removable drive cassette carrying a motor and battery power source adapted to selectively rotate the wire. The wire inserter instrument is designed to utilize a prosthetic wire of a substantially circular cross section having one or more flats or grooves to provide anti rotational keying with the chuck which is used for installation.. The wire is constructed with a spade tip specifically designed to cut a hole in the bone smaler in diameter than the major diameter of the wire so that the cutting action of the spade tip is realized while retaining a tight fit between the bone and the wire. This cutting action is achieved by restricting the cutting edges of a conventional spade point to a width less than the wire diameter. The novel wire thus achieves the desired functions of the previously described wire but is more easily gripped and installed than those prior art wires. Thus the wire combines the drilling ease of the spade point with the holding properties of the trocar point. Since the wire is more easily installed requiring less pressure and force to implant in the bone it results in an easier and more accurate installation than conventionally used wires. The material of construciton of the wire is stainless steel or other medically suitable material.
The above mentioned purposes are more readily apparent when read in conjunction with the following detailed description of the preferred embodiment of the present invention.